Mr Bills Mod Help Please.

[Carl-NC]

Pot voltage looks OK. Next I would measure the output voltage of U5b vs threshold setting. Do this with the coil disconnected. This should not be difficult to track down.

[keith777]

connect 6 pin of U5 on GND (lower pin of R32, C18 etc). disconnect C16. measure voltage on 7 pin U5 and write the value
and do you hear a sound or not, in ALL METAL mode.

now you are talking past my pay grade.

[keith777]

Pot voltage looks OK. Next I would measure the output voltage of U5b vs threshold setting. Do this with the coil disconnected. This should not be difficult to track down.

is this pin 6 i assume that is what you mean. you said U5b for U56 ?

[kt315]

U5b is a part of U5. there are U5a and U5b just it is dual opamp.

[keith777]

U5b is a part of U5. there are U5a and U5b just it is dual opamp.

i got 0.23 that's if i was doing it right.

[keith777]

Pot voltage looks OK. Next I would measure the output voltage of U5b vs threshold setting. Do this with the coil disconnected. This should not be difficult to track down.

i got 0.23 that's if i was doing it right.

[Carl-NC]

Output of U5b is pin 7. You want to measure it at min threshold and max threshold.

[keith777]

Output of U5b is pin 7. You want to measure it at min threshold and max threshold.

i get 2.69 Min and 2.76 Max

[Carl-NC]

Both way too high. Again, with the coil disconnected, measure the input to U5b (on pin 5). Also pin 6 at min/max threshold.

[kt315]

through holes have a metalization inside, invisible for you.

ordinary practice of all beginners to delete it while desoldering something from a pcb.
and very big problem because beginners do not know and do not want to accept the mistake they do (no accuracy and patience, also no needed temperature
mode of solder iron).
they make it left the copper on pins of deleted component desoldering. do not notice that. a contact between sides gets lost out.
now you must check that trimpot's pins' holes have good reliable electric contact from one pcb side to another one in places of the holes.

[kt315]

[kt315]

[keith777]

Both way too high. Again, with the coil disconnected, measure the input to U5b (on pin 5). Also pin 6 at min/max threshold.

I get 0.02 on Min and 0.02 on Max

[keith777]

i have already checked the wires to the pots and connections from top to bottom of the circuit board with the buzzer on the multi meter. they all seemed fine on the wires and the resisters that i changed.

[Carl-NC]

I get 0.02 on Min and 0.02 on Max

Is that pin 5 or pin 6? Need both.